1. Field of the Invention
The present invention relates to cooling plates for shaft furnaces, particularly blast furnaces, provided with refractory linings. The cooling plates are of copper or a low-alloy copper alloy and are provided with cooling agent ducts in their interiors. Each cooling plate is manufactured from a rough forged or rolled ingot, wherein the cooling plate has a straight or planar inner side and the cooling ducts are blind-end bores extending in the interior of the cooling plate, wherein the cooling plate is provided at the edge thereof with side flanges, and wherein pipe connections are provided at the ends of the cooling ducts.
2. Description of the Related Art
Copper cooling plates of the above-described type are usually arranged between the furnace shell and the brick lining of the furnace and are connected to the cooling system of the shaft furnace. On the side facing the interior of the furnace, the cooling elements in the upper portion of the shaft furnace are for the most part covered with refractory material and in the area of the body they are covered with carbon bricks.
In plates of cast copper known in the art, the cooling ducts are formed either by cast steel pipes or the cooling ducts are cast-in directly. The structure of cast copper is not as homogeneous and dense as that of forged or rolled copper. Consequently, the thermal conductivity of cast copper is also poorer and the strength is lower. In the case of cast-in pipes, the thermal conductivity is impaired by an oxide layer between the pipe and the copper block or ingot.
DE-29 07 511 discloses a cooling plate which is manufactured from a rough forged or rolled ingot and in which the cooling ducts are vertically extending blind-end bores produced by mechanical deep drilling. The structure of the cooling plate is significantly denser and more homogeneous than that of a cast copper plate. The strength values are higher than those of the cast copper plate. The desired position of the bores is precisely adhered to with respect to the horizontal and vertical directions and, thus, a uniform heat discharge is ensured.
This cooling plate is provided on the side facing the interior of the furnace with webs and grooves and can be lined with refractory bricks or with a rammed refractory substance.
EP 0 705 906 A1 discloses a cooling plate manufactured from a rough forged or rolled copper ingot in which, in addition to the vertically extending blind-end bores, cooling ducts are provided for cooling the edge zones, wherein the additional cooling ducts are provided in the form of vertical or horizontal blind-end bores having a smaller diameter and arranged in the border zones around the vertically arranged blind-end bores.
DE 195 03 912 A1 discloses a cooling plate manufactured from a rough forged or rolled copper ingot in which, in addition to the vertically extending blind-end bores, an additional cooling element is mounted in the upper or lower portion, wherein the additional cooling element is mounted either so as to be releasable or forged to the cooling plate, wherein additional vertical and horizontal blind-end bores are provided in the additional cooling element and wherein the additional blind-end bores are also connected through copper pipe connections to the cooling system of the blast furnace.
DE 195 45 048 discloses differently constructed cooling plates composed of copper or a low-alloy copper alloy with cooling agent ducts arranged in the interior of the cooling plate, wherein the cooling plate is manufactured from a rough forged or rolled ingot and wherein the cooling ducts are vertically extending blind-end bores.
The cooling plates are provided with vertical side flanges on both sides and/or with horizontal side flanges on both sides, as well as with horizontally arranged webs and grooves on the cooling body facing the interior of the furnace.
The cooling plates are constructed in such a way that the vertical or horizontal side flanges engage into each other in an overlapping manner when mounted on the furnace shell and, thus, form cooling segments or circumferential cooling rings. In one type of the cooling plate, the side flanges are arranged on the side facing the interior of the furnace, and in the other type of cooling plate the side flanges are arranged on the side facing the furnace shell.
However, the arrangement and fastening in the blast furnace of these cooling plates mentioned last have the disadvantage that a gap is formed between the cooling plates and the furnace shell, wherein this gap must be filled with refractory rammed material or with specifically cut refractory bricks. Consequently, the assembly of this cooling system is time-consuming and expensive.